Extensible lubricant-return tube for internal combustion engines

ABSTRACT

An extensible lubricant-return tube, for enclosing a pushrod in an internal combustion engine, having gaskets at the opposite ends of the tube and comprising an outer sleeve and an inner insert. The outer sleeve is internally smooth and the inner insert is externally threaded in the area where it telescopes into the sleeve. A pair of internally threaded locking torroids disposed on the inner insert serve to adjust and lock the sleeve and insert to the required length.

[ 1 Oct. 24, 1972 United States Patent Gaipo et al.

154] EXTENSIBLE LUBRICANT-RETURN 1,721,341 7/1929 Ha1ford...............123/9061X TUBE FOR INTERNAL COMBUSTION 1,993,875 3/1935 1 23/9038 ENGINES 2,103 ,024

[72] Inventors: Eugene T. Gaipo, 15035 Rayfield 2657679 12/1937 Smith..................123/9038 X 11/1953 Powell.................,..123/9038 XXXX 0000 2 3 0003 9995 ///8 333 222 1]] nwn m nu mmm a u s dm O Vkm ak ra GBSM 6926 5566 9999 1111 WWH l l 929 725 ,3 528 603 223 Drive; James E. Mattingly, 14911 Fairhope Drive, both of La Miranda, Calif. 90638 Jan. 10, 1972 [21] Appl. No.: 216,451

[22] Filed:

Primary Examiner-A1 Lawrence Smith Attorney-Ellsworth R. Roston Related US. Application Data ABSTRACT [63] Continuation-impart of Ser. No. 78,489, Oct. 6,

1970, abandoned.

An extensible lubricant-return tube, for enclosing a [52] U5. Cl. .............123/90.38, 123/9061, 184/69, pushrod in n i l combustion ngin h ing gaskets at the opposite ends of the tube and comprising an outer sleeve and an inner insert. The outer sleeve is internally smooth and the inner insert is exwuR 3 91 m41 1 a 0 ru m4fi M1 69 m0 9% 14 88 W09 mZM mrl m n 3 mm d Ld .mfi 00 55 [1 ternally threaded in the area where it telescopes into 133 A, 302 the sleeve. A pair of internally threaded locking torroids disposed on the inner insert serve to adjust and lock the sleeve and insert to the required length.

[56] References Cited UNITED STATES PATENTS 15 Claims, 4 Drawing Figures 1,718,490 6/1929 Ryder.....................123/9038 1 ll'lllll llllll llllllllllu. r

PATENTED BT I972 3.699.934

INVENTORS EUGENE T GAIPO JAMES E. MATTINGLY ATTORNEYS EXTENSIBLE LUBRICANT-RETURN TUBE FOR I INTERNAL COMBUSTION ENGINES This is a continuation-in-part of Ser. No. 78,489 filed Oct. 6, 1970, and now abandoned.

BACKGROUND Two of the most popular present day motor vehicle activities are those involving the vehicles known as Dune Buggies and as Off-The-Road Vehicles. As their names imply, the Dune Buggy is a motor vehicle that has been modified for driving and racing over sand dunes, and the Off-The-Road Vehicle is one that has been modified for off-the-road driving and for racing over hill and dale, and through streams. Since the normal motor vehicle is not designed for this type of service, much modification is required for both the vehicle body and of the engine.

Suprisingly, to those not engaged in these activities, the Volkswagen motor vehicle is widely used in these activities.

In order to more fully understand the present invention, it is desirable to introduce a slight digression at this point, the digression relating to engines, to a portion of their structure, and to their operation.

It is well-known that an internal combustion engine has one or more cylinders within which successive explosions are produced; each explosion driving a movable piston that, in turn, provides power. To achieve this result, a gaseous explosive fuel mixture must be introduced into the cylinder, and the burned gases resulting from the explosion must be exhausted from the cylinder, preparatory to producing a subsequent explosion. The movement of these gases is accomplished by valves, orv more correctly, by ports that are opened and closed by valves. The most commonly used valves are of the type known as poppet valves, and these resemble a flat-headed nail having a greatly enlarged head and an elongated shank, known as the valve-stem. When the valve' head fits tightly over the port, the valve is said to be closed; whereas, when the valve-head is raised or otherwise removed from the port, the valve is said to be open.

The valve/port used for admitting the explosive mixture to the cylinder is therefore known as the intake valve, and the valve/port used for controlling the exhausting of the burned gases is known as the exhaust valve. Each cylinder requires one valve of each type. Despite the fact that these two types of valves have different functions, different characteristics, are made of different materials, etc., they act in substantially similar manners.

As may be realized, the intake valve must be opened early to admit the explosive mixture to the cylinder, and must remain tightly closed during the explosion to prevent the leakage of power. For a similar reason, the exhaust valve must also remain tightly closed during the explosion and must then open to permit the escape of the exhaust gases. Of course, the actual opening and closing of the two valves, and their open and closed intervals must be carefully controlled and synchronized and this is generally done by a camshaft that comprises a rotating rod having a plurality of carefully designed cams thereon, each cam being located and oriented to control a particular valve.

While there are many ways of controlling the valves, one of the most commonly used methods is to have a tom end of the valve stem, as this pushrod arrangement permits a wide range of locations of the valves relative to the location of the camshaft. As the camshaft rotates, the individual cams thereon act to move the interior end of the pushrod, causing the exterior end of the pushrod, causing the exterior end of the pushrod to move accordingly. Since the exterior end of the pushrod abuts the end of the valve stem, its movement moves the valve stem and the valve head,'thus opening (or closing) that particular valve/port. A valve spring is generally used to provide the opposite direction valve movement when the orientation of the cam permits this.

In some engines, the exterior end of the pushrod (or its equivalent) acts directly on the bottom end of the valve stem, while in other engines, and in the Volkswagen engine, a so-called rocker arm arrangement is used. The rocker arm may be visualized as a teetertotter that is centrally pivoted, with the exterior end of the pushrod positioned directly under one end of the teeter-totter rocker arm. As the exterior end of the pushrod is raised by the action of the cam, it raises its associated end of the rocker arm; the pivotal arrangement thereof forces the other end of the rocker arm to move downward. As this other end of the rocker arm moves downward, it pushes down on the end of the valve stem, causing the valve head to open the valve/port.

In such a rocker arm arrangement, the amount of valve movement is controlled primarily by the cam, by the movement'of the pushrod, and by the proportions of the rocker arm, while the actual positioning of the valve relative to the crankshaft determines the necessary length of the pushrod.

It is essential that the rocker arm assembly be fully lubricated, because a failure of this mechanism might well destroy critical parts of the engine. Therefore, in order to assure proper lubrication of the rocker arm assembly, it is generally provided with lubricating oil under high pressure; the excess and used oil being permitted to drain back into a sump, from where it is again recirculated under high pressure to the parts of the engine requiring oil.

As pointed out above, the Volkswagen engine uses the rocker arm arrangement, and since the valves are located in the engine head, which is remote from the engine block, provisions must be made for lubricating the pushrods, and for returning the used oil to the sump. This is accomplished by enclosing each pushrod in an individual pushrod tube that permits the oil to drain back to the sump, meanwhile providing a clean oil vapor atmosphere for the pushrod operation.

For ordinary vehicle usage, as on paved streets and the like, the pushrod tube is not exposed to any dangerous environment, and the Volkswagen engine comes equipped with satisfactory but thin-walled pushrod tubes. However, an entirely different situation exists for the operation of Dune Buggies and Off-The- Road Vehicles. In the normal use of these vehicles, the terrain is replete with jagged rocks, sharp timbers, rubble, thrown stones, and the like. Despite the use of protective devices, such as skid-plates, frequently, but unknown to the driver, one or more of the pushrod tubes is ruptured; and the oil leaks away until the en gine overheads .and may be destroyed. A secondary problem is that the object that caused the rupture of the pushrod tube may also have bent the pushrod proper, thus degrading the vehicles operation.

OBJECTS AND DRAWINGS It is therefore the principal object of the present in- A vention to provide an improved Ofi-The-Road-Vehicle.

It is another object of the present invention to provide an improved Volkswagen engine.

It is still another object of the present invention to provide an improved pushrod tube.

It is a further object of the present invention to provide an improved pushrod tube'that may be easily retrofitted onto a Volkswagen engine.

It is a still further object of the present invention to provide an improved pushrod tube that may be easily installed as an emergency repair with minimum dismantling of the engine.

Theattainment of these objects, and others, will be realized from the following description, taken in conjunction with the drawings, of which FIG. 1 shows a pictorial partial view of an engine using pushrod tubes;

. FIG. 2 shows details of an improved pushrod tube; FIG. 3 shows another embodiment of the pushrod tube; and

FIG. 4 is a fragmentary view showing modifications in the embodiment shown in FIG. 3.

SYNOPSIS Broadly stated, the present invention disclosesan extensible pushrod tube that is telescoped to fit into an allotted space. .It is then expanded to produce an oil-tight passageway enclosing the pushrod. The novel pushrod tube is basically a telescoping arrangement using mating threads to control the overall length.

INTRODUCTION The present invention will be better understood from a study of FIG. 1, which illustrates a cutaway partial view of an engine having an engine block 11. Since the Volkswagen engine is an air-cooled four cylinder engine, it actually has four finned cylinders protruding from the engine block 11;but only one such cylinder 12 is clearly visible, its paired cylinder being hidden from view, and the other pair of cylinders being positioned on the opposite unshown side of the engine. The cylinders 12 are finned for improved cooling.

A movable piston, not shown, is located within each cylinder, and a rocker arm assembly 13 is partially visible in the cutaway portion of the engine head 14-this assembly operating as previously described.

Assume now that an engine of the above type has suffered a rupture of one of its pushrod tubes 15a, 15b,

I etc. Previously, in order to make'the necessary repairs it was necessary to first unsnap spring clamp 21, and to remove the cover 22 that closes off the valve and rocker arm assembly chamber, after which the rocker arm assembly 13 was removed. At that time it became possible to remove the pushrods, one of which is indicated at 16. The engine head 14 was then unbolted and removed, and only then was it possible to remove and replace the damaged pushrod tube 15.

A new pushrod tube-was then inserted, the engine head bolted back, making sure that each bolt was properly tensioned; the pushrods were replaced, the rocker arm assembly was re-installed, and the cover was put back into place. As may be understood, the above procedure was a time consuming, tedious operation, and if the rupture occurred during acompetition, it invariably resulted in dropping out of the race. The present invention overcomes the above problem by introducing a new telescoping pushrod'tube 31 as shown in FIG. 2. The new tube comprises a two piece (32, 33) strong, thick-wall tube of aluminum or similar metal. The outer female-type sleeve 33 is illustrated as being adapted to receive an externally threaded male-type insert 32 so that the pushrod tube 31 may be shortened or extended to any desired length. i

In use as an emergency repair, the following procedure is used. Referring back to FIG. 1, spring clamp 21 is first unsnapped, and cover 22 is carefully removed to prevent tearing the gasket between it and the engine head 14, which in this repair procedure, is not removed. Removing cover 22 as described above, exposes the entire rocker arm assembly 13, and the particular rocker arm 23 associated with the ruptured pushrod tube is slid aside to expose the pushrod opening 25 and the near end of 26 of the pushrod l6 positioned in the ruptured pushrod tube. With the individual rocker arm moved aside, the pushrod 16 is now withdrawn, as indicated in FIG. 1.

Having done this, the damaged pushrod tube is now removed, and since it is already useless because of its rupture--it may be cut, bent, twisted, or otherwise strong-armed out of its normal position. Once the damaged pushrod tube has been removed, the new pushrod tube '31 of FIG. 2 is telescoped to a longitudinal length that is short enough to'permit it to fit between engine block 11 and engine head 14. When stalled, the pushrod 16 is re-inserted; the rocker arm 23 tubes. To do this, the above procedure is followed with one exception; namely for convenience, it may be desirable to remove, the entire rocker arm assembly as a unit, rather than working with each individual rocker arm and pushrod. This retrofitting operation, of course,

provides a preventative advantage, due to the strongerthan-original construction of the pushrod tube.

It was pointed out above that the pushrod tube is a return path for permitting the'oil to flow from the rocker arm chamber to the sump in the. engine block; and since the oil becomes quite hot during its interval spent in the engine, the new pushrod tube 31 may be finned for additional cooling of the oil flowing through it-the fins acting in the well-known manner of producing a larger area that is in thermal exchange relation with the cooler ambient air.

Also, since the pushrod tube is a return path for the oil, the ends of the ends of the tube should make leakproof contact with both the engine block and the engine head. To achieve this result, the factory installation of the original pushrod tubes positioned a gasket/flange 35 of resilient material at both ends of the installed pushrod tube; i.e., between the tube and the engine block, and between the'tube and the engine head. Suitable shoulders 36 at the ends of the pushrod tube 31 engage gaskets 35. The original gaskets, or replacements therefor, should be used when installing the new pushrod tubes.

FIG. 3 shows another embodiment of the disclosed pushrod tube. In this embodiment, the female sleeve 37 is internally smooth-bored to receive the male insert 38 in a slidable manner. Also, the locking torroid 34 is shown as a knurled internally threaded ring or a pair of rings 34 and 34b which are pressed against each other and against the inner end of the sleeve 37 to lock the sleeve and the insert in fixed position in accordance with the length of the pushrod.

In installing this embodiment, the two parts 37 and 38 of the pushrod tube are telescoped far enough to fit into the allotted space, and then the overall length is expanded by turning the locking ring, which abuts the inner end of the female sleeve. This illustration also indicates cooling fins and the presence of pushrod 16.

In a preferred embodiment, deformable means such as an Q-ring 50 is disposed on the insert 38 between the inner end of the sleeve 37 and the torroid 34. The O- ring 50 may be made from a suitable material such as rubber. The O-n'ng becomes deformed when the torroid 34 becomes pressed against the inner end of the sleeve 37 so as to seal the sleeve and the insert against the leakage of lubricating oil. The inner surface of the sleeve 37 may be provided with a bevelled undercut 52 at its inner end to rest the O-ring 50 and limit the deformation of the O-ring when the torroid 34 is threaded on the insert to exert pressure against the inner end of the sleeve.

It may be desirable, under some conditions, to use an internal compression spring in the embodiment of FIG. 3; the spring being positioned inside sleeve 37, and acting to urge apart the two sections of the pushrod tube. This arrangement facilitates holding the pushrod tube in place while it is being expanded by means of the locking ring.

The terminology internally smooth-bored.and

peripheral shoulders positioned at the outer ends of said sleeve and of said insert for co-operating with the gaskets to respectively seal the sleeve and the insert against the loss of lubricating fluid; and

means disposed on said insert and internally threaded for adjustable positioning along the threaded portion of the insert to adjust the total length provided by the sleeve and the insert to conform to the length required by the pushrod said means comprising a pair of torroids which become locked against each other to fix the combined length of the sleeve and the insert.

2. The combination of claim 1 wherein said sleeve is externally finned for providing a cooling effect for the contents of said tube.

3. The combination of claim 1 wherein the extending means comprise a pair of torroids which become locked against each other to fix the combined length of the sleeve and the insert and wherein the torroids are disposed on the insert against the inner end of the sleeve to lock the sleeve and the insert against movement.

4. The combination of claim 1 wherein the extending means are disposed against the inner end of the sleeve in the locked relationship of the sleeve and the insert and wherein deformable sealing means are disposed between the inner end of the sleeve and the extending means to seal the sleeve and the insert against the leakage of lubricating fluid and wherein the inner surface of the sleeve has a bevelled undercut at its inner end to nest the deformable means when the deformable means becomes deformed by a pressure of the extending means against the inner end of the sleeve.

5. The combination of claim 4 wherein the deformable means constitutes an O-ring.

6. The combination of claim 5 wherein said internally threaded torroids comprise knurled rings.

7. The combination of claim 6 wherein the interior surface of said sleeve has fins.

8. The combination of claim 6, including a sealing flange disposed on the sleeve to define the shoulder on the sleeve and a sealing flange disposed on the insert to define the shoulder on the insert.

9. An extensible lubricant-return tube for enclosing a pushrod in an automobile engine having gaskets at the opposite ends of the pushrod, comprising:

an outer female sleeve having an interior surface and having inner and outer ends;

an inner male insert having inner and outer ends and constructed to fit telescopically into said sleeve, the insert being externally threaded at its inner end;

extending means comprising at least one internally threaded torroid positioned to threadedly engage the external threads of said insert and to abut the inner end of said sleeve for controlling and maintaining the overall length of said sleeve and said insert in accordance with the length of the pushrod; the inner surface of the sleeve being smooth and the torroid means constituting a pair of rings which press against each other and the inner end of the sleeve to facilitate the locking of the sleeve and the insert in accordance with the length of the pushrod,

a sealing flange defining a peripheral shoulder at the outer end of said sleeve for co-operating with one of the gaskets on the engine to seal the sleeve against the leakage of lubricating fluid from the sleeve; and

a sealing flange defining a peripheral shoulder at the outer end of said insert for co-operating with the outer one of the gaskets on the engine to seal the insert against the leakage of lubricating fluid from the insert.

10. The combination of claim 9 wherein deformable means are disposed on the insert between the inner end of the sleeve and the torroid means to seal the sleeve and the insert against the leakage of lubricating oil when the torroid means are threaded on the insert against the inner end of the sleeve and the inner surface of the sleeve is provided with a bevelled undercut to nest the deformable means when the torroid means are pressed against the inner end of the sleeve.

11. The combination set forth in claim 10 wherein the deformable means constitutes an O-ring.

12. In combination for use in an engine: a

an outer female sleeve having inner and outer ends and an inner surface;

an inner male insert having inner and outer ends and having an externally threaded outer surface at its inner end, the insert being constructed to fit telescopically into said sleeve;

a pushrod disposed within said sleeve and said insert;

internally threaded locking means and disposed on the insert to engage the external threads of said insert and to abut the inner end of the sleeve;

the inner surface of the sleeve being smooth and the locking means comprising a pairof rings which press against each other and the inner end of the sleeve to lock the sleeve and the insert in fixed position;

a flange positioned at the outer end of said sleeve to define a first peripheral shoulder;

a flange positioned at the outer end of said insert to define a second peripheral shoulder;

a first gasket disposed against the first peripheral shoulder to seal the sleeve against the leakage of lubricating oil; and

a second gasket disposed against the second peripheral shoulder to seal the insert against the leakage of lubricating oil.

13. The combination of claim 12 wherein deformable means are disposed on the insert between the inner end of the sleeve and the locking means to seal the sleeve and the insert against the leakage of lubricating oil when the locking means are threaded on the insert against the inner end of the sleeve and wherein the inner surface of the sleeve is provided with a bevelled undercut to ,nest the deformable means when the locking means are pressed against the inner end of the sleeve.

14. The combination set forth in claim 13 wherein the deformable means constitutes an O-ring.

15. The combination set forth in claim 14 wherein the inner surface of the sleeve is provided with a bevelled undercut to nest the O-ring when the rings are pressed against the inner end of the sleeve. 

1. An extensible lubricant-return tube for enclosing a pushrod in an automobile engine having gaskets at the opposite ends of the tube, the combination comprising: an outer female sleeve having inner and outer ends; an inner male insert having inner and outer ends and constructed to fit telescopically into said sleeve, the male insert being externally threaded along at least part of its length at the inner end; the internal surface of said sleeve being smooth peripheral shoulders positioned at the outer ends of said sleeve and of said insert for co-operating with the gaskets to respectively seal the sleeve and the insert against the loss of lubricating fluid; and means disposed on said insert and internally threaded for adjustable positioning along the threaded portion of the insert to adjust the total length provided by the sleeve and the insert to conform to the length required by the pushrod said means comprising a pair of torroids which become locked against each other to fix the combined length of the sleeve and the insert.
 2. The combination of claim 1 wherein said sleeve is externally finned for providing a cooling effect for the contents of said tube.
 3. The combination of claim 1 wherein the extending means comprise a pair of torroids which become locked against each other to fix the combined length of the sleeve and the insert and wherein the torroids are disposed on the insert against the inner end of the sleeve to lock the sleeve and the insert against movement.
 4. The combination of claim 1 wherein the extending means are disposed against the inner end of the sleeve in the locked relationship of the sleeve and the insert and wherein deformable sealing means are disposed between the inner end of the sleeve and the extending means to seal the sleeve and the insert against the leakage of lubricating fluid and wherein the inner surface of the sleeve has a bevelled undercut at its inner end to nest the deformable means when the deformable means becomes deformed by a pressure of the extending means against the inner end of the sleeve.
 5. The combination of claim 4 wherein the deformable means constitutes an O-ring.
 6. The combination of claim 5 wherein said internally threaded torroids comprise knurled rings.
 7. The combination of claim 6 wherein the interior surface of said sleeve has fins.
 8. The combination of claim 6, including a sealing flange disposed on the sleeve to define the shoulder on the sleeve and a sealing flange disposed on the insert to define the shoulder on the insert.
 9. An extensible lubricant-return tube for enclosing a pushrod in an automobile engine having gaskets at the opposite ends of the pushrod, comprising: an outer female sleeve having an interior surface and having Inner and outer ends; an inner male insert having inner and outer ends and constructed to fit telescopically into said sleeve, the insert being externally threaded at its inner end; extending means comprising at least one internally threaded torroid positioned to threadedly engage the external threads of said insert and to abut the inner end of said sleeve for controlling and maintaining the overall length of said sleeve and said insert in accordance with the length of the pushrod; the inner surface of the sleeve being smooth and the torroid means constituting a pair of rings which press against each other and the inner end of the sleeve to facilitate the locking of the sleeve and the insert in accordance with the length of the pushrod, a sealing flange defining a peripheral shoulder at the outer end of said sleeve for co-operating with one of the gaskets on the engine to seal the sleeve against the leakage of lubricating fluid from the sleeve; and a sealing flange defining a peripheral shoulder at the outer end of said insert for co-operating with the outer one of the gaskets on the engine to seal the insert against the leakage of lubricating fluid from the insert.
 10. The combination of claim 9 wherein deformable means are disposed on the insert between the inner end of the sleeve and the torroid means to seal the sleeve and the insert against the leakage of lubricating oil when the torroid means are threaded on the insert against the inner end of the sleeve and the inner surface of the sleeve is provided with a bevelled undercut to nest the deformable means when the torroid means are pressed against the inner end of the sleeve.
 11. The combination set forth in claim 10 wherein the deformable means constitutes an O-ring.
 12. In combination for use in an engine: an outer female sleeve having inner and outer ends and an inner surface; an inner male insert having inner and outer ends and having an externally threaded outer surface at its inner end, the insert being constructed to fit telescopically into said sleeve; a pushrod disposed within said sleeve and said insert; internally threaded locking means and disposed on the insert to engage the external threads of said insert and to abut the inner end of the sleeve; the inner surface of the sleeve being smooth and the locking means comprising a pair of rings which press against each other and the inner end of the sleeve to lock the sleeve and the insert in fixed position; a flange positioned at the outer end of said sleeve to define a first peripheral shoulder; a flange positioned at the outer end of said insert to define a second peripheral shoulder; a first gasket disposed against the first peripheral shoulder to seal the sleeve against the leakage of lubricating oil; and a second gasket disposed against the second peripheral shoulder to seal the insert against the leakage of lubricating oil.
 13. The combination of claim 12 wherein deformable means are disposed on the insert between the inner end of the sleeve and the locking means to seal the sleeve and the insert against the leakage of lubricating oil when the locking means are threaded on the insert against the inner end of the sleeve and wherein the inner surface of the sleeve is provided with a bevelled undercut to nest the deformable means when the locking means are pressed against the inner end of the sleeve.
 14. The combination set forth in claim 13 wherein the deformable means constitutes an O-ring.
 15. The combination set forth in claim 14 wherein the inner surface of the sleeve is provided with a bevelled undercut to nest the O-ring when the rings are pressed against the inner end of the sleeve. 